Lance tube deflection compensator for long retracting blower



NOV. 9, 1965 w, MCCOLL 3,216,045

LANCE TUBE DEFLECTION COMPENSATOR FOR LONG RETRACTING BLOWER Filed April 22. 1964 4 Sheets-Sheet 1 INVENTOR. v/z/fikm' )X: 54/].

' jaw, algal Nov. 9, 1965 w. MCCOLL 3,216,045

LANCE TUBE DEFLECTION COMPENSATOR FOR LONG RETRAGTING BLOWER Nov. 9, 1965 w. Mcco 3,216,045

LANCE TUBE DEFLECTION COMPENSATOR FOR LONG RETRACTING BLOWER Filed April 22, 1964 4 Sheets-Sheet 3 ,9 aR/vE/i Nov. 9, 1965 w. M COLL 3,216,045

LANCE TUBE DEFLECTION COMPENSATOR FOR LONG Filed April 22, 1964 RETRACTING BLOWER 4 Sheets-Sheet 4 [I 1F mun E 6Zf,e...,

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United States Patent 3,216,045 LANQE TUBE DEFLECTION COMPENSATOR FQR LONG RETRACTING BLOWER William McColl, Southampton, England, assignor to Diamond Power Specialty Corporation, Lancaster,

Qhio, a corporation of Ohio Filed Apr. 22, 1964, Ser. No. 361,831 3 filairns. (Cl. 315-317) The present invention broadly relates to apparatus for cleaning the surfaces of heat exchanger apparatus such as high capacity power boilers and the like, and more particularly to cleaning apparatus of the type employing an elongated cleaning tube provided with at least one nozzle in the forward end thereof and which tube is movable to and from a retracted position and a projected position within the interior of the heat exchanger apparatus during which travel a pressurized blowing medium is discharged against the surfaces to be cleaned. More specifically, the present invention is directed to an improved cleaning apparatus of the type conventionally referred to as a soot blower which is of the long travel or long retracting type and which is provided with compensating means at the forward end thereof that is operable in coordinated relationship relative to the projecting :position of the cleaning or lance tube into the interior of the heat exchanging apparatus so as to compensate for the vertical deflection of the lance tube providing for a substantially linear path of travel of the nozzle end portion of the lance tube.

Cleaning apparatuses or soot blowers of the aforementioned type are in widespread use in industry for effecting a removal of soot, slag, as well as other extraneous deposits from the surfaces of heat exchanger apparatuses of various types. Soot blowers of the so-called long-retracting or long travel type incorporate a relatively long cleaning or lance tube which is adapted to be disposed exteriorly of and in alignment with a wall port in the wall of a heat exchanger apparatus and is movable from a retracted position in which the forward or nozzle end of the lance tube is disposed contiguous to a wall port to a projected position in which the lance tube extends into the interior of the heat exchanger apparatus. The lance tube is conventionally rotated during its longitudinal movement to and from the retracted and projected position and a pressurized blowing medium such as steam or air, for example, is discharged from one or a plurality of nozzles formed in the forward end portion of the lance tube. The impingement of the pressurized blowing medium against the heat exchanger surfaces effects a removal of the soot, slag, and other deposits from the surfaces maintaining a high thermal efficiency of the heat exchanger apparatus.

Increases in the size and the capacity of modern high pressure power boilers has necessitated a corresponding increase in the length of the lance tube of long retracting type soot blowers in order to achieve adequate cleaning coverage of the tube banks including the pendant type superheater and reheater bundles disposed within the interior of the boiler. The desirability of grouping the tube bundles in a relatively close nested relationship to provide for optimum heat transfer between the tube bundles and the hot combustion gases necessitates that the cavities provided through which the lance tube travels during its projecting and retracting cleaning movement be of a moderate cross sectional area. It is also necessary that the path of travel of the nozzle end of the lance tube from which the pressurized blowing medium is discharged be carefully controlled so as to provide substantially uniform cleaning coverage of the heat exchanger surfaces while concurrently avoiding any mechanical interference between the lance tube and the tube bundles and attendant supporting structure.

The progressive increases in the length of the lance tubes of long retracting type soot blowers has occasioned a problem as a result of the gravitational deflection of the lance tube when it extends in unsupported relationship into the interior of the heat exchanger apparatus during its projecting and retracting travel. The gravitational deflection of the lance tube results in an arcuate path of travel of the nozzle end portion of the lance tube which results in mechanical interference with the tube bundles and attendant structures or alternatively requires a substantially increased cross sectional area of the cavity through which the lance tube travels. The progressive vertical deflection of the nozzle end portion of the lance tube relative to a true linear path of travel as the lance tube is moved from a retracted to a fully projected position, also causes a deviation in the distance between the nozzles and the adjacent heat exchanger surfaces to be cleaned resulting in a non-uniform cleaning pattern. Gravitational deflection of the lance tube presents the further problem of causing an undesirable thermal shock and erosion of the tube bundles and heat exchanger surfaces which are subject to the direct close impingement of the blowing medium as the result of the non-linear travel of the nozzle end portion of the lance tube as it is advanced into a linearly aligned cavity through the tube bundles,

In an attempt to overcome lance tube deflection and the problems associated therewith, various structural design modifications of the lance tube have been used or proposed for use. These changes, however, have been unsuccessful in eliminating lance tube deflection and frequently have resulted in an increase in the weight, complexity and cost of long travel type soot blowers. Attempted redesign of the power boiler to provide for a cavity which accommodates a lance tube subject to gravitational deflection, constitutes a commercially impractical solution to this problem.

It is accordingly a principal object of the present invention to provide an improved soot blower of the long retracting type which overcomes the problems associated with lance tube deflection which are present in soot blowers of similar types heretofore known.

Another object of the present invention is to provide a long retracting type soot blower employing compensating means thereon which is operable in coordinated relationship with the length of the inward projecting unsupported portion of the lance tube to effect a correction in the gravitational deflection thereof thereby providing for a substantially linear or controlled path of travel of the nozzle end portion of the lance tube.

Still another object of the present invention is to provide an improved long retracting type soot blower which is of simple design, durable operation, economical manufacture and which incorporates compensating means therein for compensating for the vertical deflection of the nozzle end of the lance tube consistent with such factors as the length of the lance tube, the specific direction of travel thereof, and the clearance and obstacles present in the cavity through the heat exchanger surfaces through which it travels.

Other objects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a fragmentary longitudinal side elevational view with portions thereof broken away for clarity of a soot blower of the long retracting type incorporating compensating means therein in accordance with the preferred practice of the present invention;

FIGURE 2 is a fragmentary perspective view partially diagrammatic illustrating the drive mechanism for concurrently etfecting translation and rotation of the lance -39 tube and for providing a coordinated lifting and lowering movement of the front supporting means;

FIGURE 3 is a fragmentary transverse sectional view of the carriage of the long retracting soot blower shown in FIGURE 1 and taken along the line 33 thereof;

FIGURE 4 is an enlarged fragmentary transverse sectional view of the front lance tube support as-shown in FIGURE 1 and taken along the line 44 thereof;

FIGURE 5 is an enlarged fragmentary side elevational view partly in section of the front support shown in FIG- URE 4;

FIGURE 6 is a fragmentary side elevational view of the rear portion of an alternate construction of a long retracting type soot blower to which the present invention is applicable;

FIGURE 7 is an enlarged transverse sectional view of an alternate satisfactory means for effecting coordinated movement of the front support relative to the advancing and retracting movement of the soot blower of the type shown in FIGURE 6;

FIGURE 8 is a fragmentary side elevational view of an alternate satisfactory arrangement for actuating the front support compensating means in response to the advancing and retracting movement of the lance tube;

FIGURE 9 is an enlarged fragmentary transverse sectional view of the front support means driven in accord ance with the arrangement shown in FIGURE 8, and

FIGURE 10 is a graphical illustration of the vertical deflection of the nozzle end of a typical lance tube as a function of the longitudinal projecting position thereof into the heat exchanger apparatus.

Referring now in detail to the drawings and as may be best seen in FIGURE 1, a soot blower of the long retracting type is illustrated which is disposed exteriorly of a heat exchanger apparatus with its lance tube 10 positioned in alignment with a wall port 12 in a wall 14 of the heat exchanger apparatus such as a high power boiler or the like. A carriage 16 is movably supported for longitudinal movement on a track plate 18 affixed to the lower flange "or web of an I-beam or rail 20 and extends for substantially the entire length thereof. The carriage 16 is longitudinally movable along the track plate 18 to and from a fully retracted position as shown in FIGURE 1 to a projected position in which the carriage is positioned adjacent to the forward or right hand end of the rail 20 as viewed in FIGURE 1, adjacent to the wall 14 of the heat exchanger apparatus. The soot blower is preferably provided with a suitable shroud or cover 21 to protect the operative components from the deposition of dirt or other deposits.

The rearward end portion of the lance tube 10 is rotatably supported by the carriage 16 and the forward end portion of the lance tube when in the fully retracted position is movably and rotatably supported by a compensator assembly indicated at 22 to prevent sagging of the lance tube due to gravitational deflection. An auxiliary intermediate support assembly 24 is preferably provided for movably and rotatably supporting the lance tube at an intermediate point therealong. The support assembly 24 comprises a trolley 26 movably mounted on the track plate 18 and incorporating a roller bracket assembly 28 through which the lance tube extends and is rotatably supported thereby. The forward end portion of the lance tube is formed with at least one aperture or nozzle indicated at 30 through which a pressurized blowing medium is discharged during the operating cycle of the soot blower. When the soot blower is in the fully retracted position as shown in FIGURE 1, the nozzle end portion of the lance tube is positioned within the wall port 12 out of direct contact with the hot combustion gases within the interior of the heat exchanger apparatus.

Pressurized blowing medium is supplied to the interior of the lance tube 10 by means of a feed tube 32 which is stationarily connected at its rearward end to a supply valve 34 and extends therefrom forwardly and is disposed in sealed sliding telescopic relationship within the lance tube 10. The feed tube 32 is of a length greater than the longitudinal movement of the carriage 16 such that the interior of the feed tube remains in continuous communication with the interior of the lance tube in all positions of travel of the carriage and lance tube connected thereto. An auxiliary feed tube support indicated at 36 is preferably provided for supporting an intermediate section of the feed tube as the carriage moves toward a fully projected position to prevent gravitational deflection or sagging of the feed tube.

A drive mechanism in accordance with one embodiment of the present invention for effecting movement of the carriage and the lance tube carried thereby to and from the retracted and projected positions and the concurrent rotation of the lance tube during its projecting and re tracting travel is best illustrated in FIGURES 1-3. As shown in these figures, a rack 38 is affixed to the underside of the track plate 18 and extends centrally thereof for substantially the entire length of the rail. A pinion 40 as shown in FIGURES 2 and 3 is disposed in constant meshing relationship with the rack 38 and is keyed or otherwise afiixed to a cross shaft 42 rotatably supported on a housing 44 of the carriage. A worm wheel 46 is afiixed to one end of the cross shaft 42 and is disposed in constant meshing relationship with a worm 48 mounted on a drive shaft 50. The cross shaft 42 as best seen in FIGURE 3, also serves to rotatably mount a pair of rollers 52 disposed in transversely spaced relationship and positioned in rolling bearing contact against the lower outer edge surface of the track plate 18. The carriage housing 44 is formed with a pair of upstanding arms or lugs 54 on which a second pair of rollers 56 are rotatably mounted and which in turn are disposed in rolling bearing contact against the upper outer edge surfaces of the track plate 18. The vertical alignment of the rollers 56 and rollers 54 enable longitudinal tilting movement of the carriage as occasioned by a controlled lifting and lowering of the lance tube by the front compensator support assembly 22 for the purposes subsequently to be described.

In the exemplary embodiment as shown in FIGURES 2 and 3, the drive shaft 50 to which the worm 48 is affixed, is drivingly coupled by means of a driven sprocket 58 affixed to the drive shaft around which a chain 60 is trained and disposed in engaging relationship with a drive sprocket 62 slidingly disposed on a square shaft, indicated at 64, which extends for the full length of the soot blower. The rearward end of the square shaft 64 is rotatably supported in a suitable pillow block 66 as indicated in FIGURE 1, while the front end portion thereof is drivingly coupled to the output shaft of a suitable gear reducer 68. A reversible electric motor 70 or other suitable fluid-actuated motor is drivingly coupled to the input shaft of the gear reducer 68 and is operative on energizati'on thereof to effect rotation of the square shaft and a corresponding advancing or retracting movement of the carriage 16. Rotation of the lance tube 10 as best seen in FIGURE 2, is similarly achieved by means of a driven sprocket 72 affixed to the lance tube which is drivingly coupled to a drive sprocket 74 slidably mounted on the square shaft 64 by means of a drive chain 76 trained around the driven sprocket '72 and drive sprocket 74. The gear reducer 68 in the embodiment shown in FIGURES 15 is also drivingly coupled to the front compensating support assembly 22 in a manner and for the purposes subsequently to be described.

Energization of the reversible electric drive motor 70 or the supply of a pressurized driving fluid to a suitable reversible fluid-actuated motor can be achieved manually or remotely by the operator or, alternatively, can be achieved in accordance with a preselected sequentially phased operating cycle as provided by an automatic control system. On energization of the reversible motor,

. the carriage commences to advance toward the projected position or to the right as viewed in FIGURE 1 until the carriage or a suitable actuator mounted thereon trips forward limit switch LSF or other suitable sensing device which signals the central control circuit and which reverses the direction of rotation of the motor 70 causing the carriage to commence its retracting travel. When the carriage attains the fully retracted position, a suitable sensing device such as a rear travel limit switch LSR is actuated which signals the control circuit and deenergizes the reversible drive motor. Accordingly, the carriage and the lance tube remain in the fully retracted position preparatory to the next cleaning cycle.

The discharge of the pressurized cleaning fluid from the nozzle 30 in the forward end of the lance tube is controlled by the actuation of the poppet-type supply valve 34 having its outlet port connected in communication with the rear end of the feed tube 32 as shown in FIGURE 1. The supply valve 34 is connected to a header 78 containing the pressurized blowing medium such as air or steam, for example, to which the supply valves of other soot blowers are similarly connected. The supply valve 34 is preferably mechanically operated such as by a linkage 78 as best seen in FIGURE 6, which is connected to .a pivotally mounted slotted cam 80 disposed on one side of the rail 20. A perforated bar 82 incorporating an actuator 84 adjustably positioned in one of the perforations thereof is mounted on the upwardly extending arms 54 of the carriage and is operative in response to the advancing movement of the carriage to coact with and rotate the slotted cam 80 in a counterclockwise direction as viewed in FIGURE 6. The arcuate pivoting movement of the slotted cam 80 in turn effects actuation of a lever 86 on the supply valve 34 effecting a controlled discharge of pressurized blowing medium from the nozzle end of the lance tube. The slotted cam 80 is rotated in a clockwise direction by the actuator 84 during the latter portion of the retracting movement of the carriage closing the valve 34 and stopping the supply of blowing medium to the lance tube. Alternatively, the supply valve 34 can be actuated by a suitable solenoid, for example, operative in response to the tripping of a limit switch by the carriage in response to its movement between the fully retracted and fully projected positions.

Since the nozzle end portion of the lance tube 10 when in the fully retracted position as shown in FIGURE 1 is disposed within the interior of the wall port 12, it is necessary to delay the discharge of blowing medium from the nozzle 30 until the lance tube has moved to a projected position beyond the water wall tubes 88 disposed along the interior surface of the wall 14 of the heat exchanger apparatus. Similarly, the discharge of blowing medium is discontinued during the retracting movement of the lance tube when the nozzle end portion thereof approaches the water wall tubes 88. The delayed discharge of blowing medium is easily achieved in accordance with the linkage arrangement as illustrated in FIG- URE 6 by adjustably positioning the actuator 84 along the length of the perforated bar 82 at a position spaced from the slotted cam 80 so that the cam 80 is not actuated until the lance tube has been advanced sufiiciently beyond the water wall tubes. This arrangement also provides for the closing of the supply valve by the actuation of the slotted cam 80 when the carriage approaches the fully retracted position at which point the nozzle end portion thereof approaches the water wall tubes 88.

It will be apparent from the description of the long retracting type soot blower constructed in accordance with the embodiment as illustrated in FIGURES 1-5 that as the lance tube 10 is moved from the fully retracted position as shown in FIGURE 1 toward the fully projected position, the nozzle end portion thereof will progressively bend downwardly in response to the gravitational bending or deflection of the unsupported over-hanging portion of the lance tube projecting forwardly of the front compensator support assembly 22 positioned adjacent to the wall port 12. A graphical illustration of the vertical gravitational deflection of the nozzle end portion of a typical lance tube is illustrated in FIGURE 10 as a function of the projecting position of the lance tube beyond the front compensator support assembly. The vertical deflection as shown in the graph is expressed in terms of inches of deflection of the nozzle end portion below a horizontal linear path. It will be noted that during the first 8 to 10 feet of projecting travel, the nozzle path is substantially linear and thereafter gravitational deflection effects a progressively greater deviation from a linear path attaining a magnitude of almost 3 feet at a point of maximum projection of a lance tube having a length of about 45 feet. Deflections of this magnitude obviously require a comparatively large cavity in the tube bundle to provide for satisfactory clearance. Deflections of this magnitude also cause a substantial unevenness in the cleaning pattern provided by the pressurized blowing medium discharged from the nozzles in the end of the lance tube.

In accordance with the present invention, this downward deflection of the lance tube is automatically compensated for by the front compensator support assembly 22 effecting a controlled raising and lowering of the lance tube movably supported thereby in a manner so that the nozzle end portion thereof travels in a substantially linear path. This not only enables the use of long retracting type soot blowers in cavities of comparatively small cross sectional area, but further improves the uniformity of the cleaning of the heat exchanger surfaces traversed by the high pressure blowing medium discharged from the nozzles.

The front compensator support assembly 22 for the soot blower embodiment illustrated in FIGURES 1-3 i best seen in FIGURES 4 and 5. As shown in FIG- URES 4 and 5, the compensator assembly 22 comprises a yoke-shaped member having the upper end thereof rigidly aflixed to the underside of the track plate 18 at a point adjacent to the forward end of the rail 20. The yoke member 90 is formed with an elongated aperture 92 therethrough through which the lance tube 10 extends and is vertically movable in response to the raising and lowering movement of a roller support member 94 positioned therebelow. The roller support member 94 is formed with a pair of transversely spaced rollers 96 rotatably supported on pins 98 which are adapted to be disposed in rolling sliding contact with the peripheral surface of the lance tube 10. The support member 94 is guidably supported for movement transversely of the path of travel of the lance tube by means of a pair of guide shafts 100 slidably disposed and guidably supported in a pair of cylindrical bosses 102 aflixed to and extending rearwardly from the yoke member 90. A coil spring 104 is positioned around the lower portion of each of the guide shafts 100 and between the support member 94 and the lower surface of the cylindrical bosses 102 effecting a downward biasing of the support member.

The downward biasing force of the coil springs 104 is counteracted by a contoured cam 106 which is positioned with its peripheral surface in rolling bearing contact against a cam follower 108 rotatably mounted in the center of the support member 94. The cam 106 is mounted on a shaft 110 and is rotatable as a result of the coaction between a worm wheel 112 afiixed thereon which is disposed in constant meshing relationship with a worm 114 mounted on a cross shaft 116. The cam shaft 110 is rotatably supported at its ends in bearings 118 mounted in opposite walls of a box-shaped section 120 along the lower portion of the yoke member 90. The cross shaft 116 similarly is supported in bearings 122 in opposing ends of the box-shaped section 120.

Rotation of the cross shaft 116 and corresponding rotation of the cam 106 is achieved in accordance with the embodiment of FIGURES 1-5 by a vertical drive shaft 124 coupled to a second output shaft 126 of the gear reducer 68 which is formed at its lower end with a bevel gear 128 disposed in constant relationship with a driven bevel gear 130 affixed to the end of the cross shaft 116. In accordance with this arrangement the energization of the reversible motor 70 effects concurrent rotation of the square shaft 64 coupled to the carriage of the soot blower effecting longitudinal movement of the lance tube and rotation thereof and concurrently effects rotation of the cam 106 effecting a controlled elevating and lowering movement of the roller support member 94 effecting movement of the lance tube 10 supported thereby to and from a lowered position as shown in solid lines in FIGURE 4 to a raised position as shown in phantom. Since the cam 106 is driven through a fixed gear reduction ratio and the carriage similarly is driven through a fixed gear reduction ratio, the relative ratios of the two drive mechanisms are proportioned so as to effect a rotation of the cam and a corresponding controlled lifting and lowering movement of the lance tube in coordinated relationship relative to the projecting length of the lance tube extending forwardly of the front compensator support assembly 22 into the interior of the heat exchanger apparatus. The relative movement of the front compensator support assembly 22 is established by the peripheral contour of the cam 106 and the contour in turn is controlled to effect a lifting or lowering movement of the lance tube so as to maintain the nozzle end thereof in a linear path of travel and compensate for the gravitational deflection of the lance tube in accordance with the graph as illustrated in FIGURE 10. h

In operation, with the lance tube and the carriage 1n the fully retracted position, energization of the motor 70 (FIGURE 4) effects an advancing movement of the carriage and lance tube toward the projected position and concurrent rotation of the cam 106. During the first 8 or 10 feet of travel, in accordance with the deflection characteristics of the lance tube as typified in FIGURE 10, no lifting movement of the roller support member 94 occurs. When the lance tube attains a projected position of about 8 to 10 feet, the cam 106 has been rotated to a point wherein the radius of its peripheral surface progressively increases imparting a lifting movement to the lance tube. This lifting movement is controlled so as to exactly compensate for the downward gravitational deflection of the lance tube maintaining its nozzle end in a true linear path. The lifting movement of the lance tube, in accordance with the contour of the cam 106, continues as the lance tube advances towards the fully projected position. The carriage 116 similarly is tilted upwardly in response to the lifting movement of the lance tube which is provided by the rollers 52 and 56 in bearing contact with the track plate 18 as best illustrated in FIG- URE 3. As the carriage approaches the fully projected position, movement of the carriage along the track plate 18 effects an upward angular swinging movement of the lance tube passing over the rollers 96 on the roller support member effecting an upper swinging movement of the nozzle end of the lance tube. Accordingly, the cam 106 is contoured along its periphery so. as to effect a lowering movement of the roller support member 94 during the last portion of the projecting travel of the lance tube maintaining the nozzle end portion along a true linear path of travel.

Upon reversal of the direction of travel of the lance tube, the roller support member initially rises as the carriage retracts away from the front compensator support assembly 22 and thereafter gradually lowers to its original position as the overhanging portion of the lance tube in the interior of the heat exchanger decreases. Accordingly, the path of travel of the nozzle end portion of the lance tube is maintained in a substantially linear path of travel during the course of its projecting and retracting travel whereupon the pressurized blowing medium discharged from the nozzle 30 effects a substantially uniform cleaning of the heat exchanger surfaces traversed thereby.

In order to accommodate the vertical compensating movement of the lance tube as provided by the front compensator support assembly 22, the Wall port 12 in the wall 14 of the heat exchanger apparatus is provided with a suitable movable or floating sealing member indicated at 132 which is slidably supported in a U-shaped frame 134 and is movable therein in response to the upward and downward movement of the lance tube. The sealing member 132 is formed with a stepped bore 136 including a narrow portion 138 adapted to be disposed in sliding bearing contact against the periphery of the lance tube 10. A pair of outwardly extending flanges 140 are affixed to the web defining the stepped bore 136 and narrow portion 138 and form a substantially airtight seal within the U-shaped frame 134. The angular section 142 between the narrow portion 138 and the outwardly directed flared portion of the stepped bore 136 provided with a plurality of circumferentially spaced apertures or ports 144 through which pressurized air is discharged effecting a sealing of the wall port and preventing escape of hot combustion gases from within the interior of the heat exchanger apparatus. Sealing air is introduced into the chamber formed between the sealing member 122 and the U-shaped frame 134 by means of a supply line 146 having its outlet end in communication therewith.

An alternative satisfactory arrangement for effecting a coordinated drive of the front compensator support-assembly and the carriage is illustrated in FIGURES 6 and 7 wherein like numerals are employed to designate like parts previously described in connection with FIGURES 15. As illustrated in FIGURE 6, the carriage 16 \and the lance tube 10 supported thereby is directly driven by a suitable reversible fluid or electrical motor 148 drivingly coupled by a chain or belt 150 to the drive shaft for effecting translation and rotation of the lance tube. Corresponding coordinated driving of the front compensator support assembly 22' as illustrated in FIGURE 7, is provided by a second reversible motor 152 drivingly coupled to the input shaft of a gear reducer 154 having its output shaft drivingly coupled to the cross shaft 116 incorporating the worm 114 thereon disposed in meshing relationship with the worm wheel 112 for effecting coordinated rotation of the cam 106. The front compensator support assembly 22 in other respects is identical to that previ ously described in connection with FIGURES 4 and 5.

In accordance with the arrangement as illustrated in FIGURES 6 and 7, energization of the motor 148 on the carriage and energization of the motor 152 of the compensator support assembly 22' are achieved concurrently in response to the automatic control system or remotely by the operator. The ratio of gear reductions are controlled so as to rotate the cam 106 in coordinated relationship relative to the longitudinal projecting position of the lance tube maintaining the nozzle end portion thereof in a substantially linear path of travel. When the carriage attains the fully projected position as signaled by the tripping of the forward limit switch, a reversal of the direction of rotation of both the motor 148 on the carriage and the motor 152 on the compensator assembly is achieved effecting appropriate compensation against the vertical deflection of the lance tube during its retracting travel.

In accordance with a preferred embodiment of the present invention, the motor 148 on the carriage is deenergized in response to a tripping of rear limit switch LSR (FIGURE 1), while deenergization of the motor 152 of the compensator assembly is achieved in response to the tripping of limit switch LS1 (FIGURE 7) by an actuator 156 mounted on the cam 106 in a position corresponding to the starting position of the cam at the initiation of the operating cycle of the soot blower. Separate deenergization of the drive motor 152 assures that the cam 106 will be in the appropriate position at the initiation of each of the soot blower operating cycles in spite of slight variations in the speed of travel of the lance tube as provided by the drive motor 148.

Still another alternative satisfactory method of achieving a coordinated drive of the front compensator support assembly relative to the translation of the lance tube is illustrated in FIGURES 8 and 9 wherein like parts are designated by like numerals previously employed. As illustrated in FIGURE 8 the long retracting type soot blower is similar to that illustrated in FIGURE 1 employing a square shaft 64 drivingly coupled to a gear reducer 68 which is operative through the arrangement illustrated in FIGURE 2 to eflect concurrent translatory and rotary movement of the lance tube 10. Coordinated movement of the front compensator support assembly 22" is achieved in the present instance as illustrated in FIG- URES 8 and 9 by employing a continuous chain 158 having one link of its upper flight indicated at 160 affixed to the carriage 16 of the soot blower and movable in response to the translatory movement thereof. The chain 158 is trained around an idler sprocket 162 rotatably mounted at the rearward end portion of the soot blower. The forward end of the chain 158 is trained around a driven sprocket 164, which as shown in FIGURE 9, is drivingly coupled to a speed reducer 166. The output shaft of the speed reducer 166 is in turn drivingly coupled to the cross shaft 116 having the worm 114 thereon which is disposed in constant meshing relationship with the Worm wheel 112 drivingly coupled to the cam 106. According to this arrangement, rotation of the cam 106 and corresponding lifting and lowering movement of the roller support member 94 and the lance tube 10 supported thereby is achieved in response to the travel of the chain 158 as a result of the longitudinal travel of the soot blower carriage.

It is also contemplated within the scope of the present invention that in lieu of employing the square drive mechanism as described in connection with the long retracting type soot blower illustrated in FIGURES l and FIG- URE 8, both the soot blower carriage and the front compensator mechanism can be driven by means of the chain 158 as illustrated in FIGURE 8, such as, for example, by employing a suitable reversible motor coupled to the idler sprocket 162 or the sprocket 164. Regardless of the specific type of drive mechanism employed for moving the lance tube, the controlled lifting and lowering movement of the front end of the lance tube by the front compensator support assembly is achieved in coordinated relationship with respect to the longitudinal projecting position of the lance tube into the interior of the heat exchanger apparatus.

While it will be apparent that the preferred embodiments herein illustrated are well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. A long retracting type soot blower comprising a frame mounted exteriorly of a heat exchanger apparatus, guide means on said frame and extending longitudinally thereof, a carriage movably mounted on said guide means, a lance tube formed with at least one nozzle in the forward end thereof for discharging a blowing medium against the heat exchanger surfaces to be cleaned, said lance tube adapted to be positioned exteriorly of and in alignment with a port in a wall of a heat exchanger apparatus and movable to and from a retracted position wherein the nozzle end of said lance tube is disposed adjacent to the port and a projected position within the interior of the heat exchanger apparatus, the rearward end portion of said lance tube supported by said carriage in substantially constant spaced relationship from said guide means during the travel thereof between said retracted and said projection position, support means mounted on said frame at a longitudinally stationary position relative to said guide means for movably supporting said lance tube at a position adjacent to the port, said support means including means movable in a direction transverse to the path of travel of said lance tube for effecting a controlled lifting and lowering of said lance tube supported thereby in coordinated relationship relative to the projecting length of said lance tube beyond said support means into the interior of the heat exchanger apparatus and in an amount to compensate for the downward gravitational deflection of said nozzle end thereof.

2. A long retracting type soot blower comprising a frame mounted exteriorly of a heat exchanger apparatus, guide means on said frame and extending longitudinally thereof, a carriage movably mounted on said guide means, a lance tube formed with at least one nozzle in the forward end thereof for discharging a blowing medium against the heat exchanger surfaces to be cleaned, said lance tube adapted to be positioned exteriorly of and in alignment with a port in a wall of a heat exchanger apparatus and movable to and from a retracted position wherein the nozzle end of said lance tube is disposed adjacent to the port and a projected position within the interior of the heat exchanger apparatus, the rearward end portion of said lance tube supported by said carriage in substantially constant spaced relationship from said guide means during the travel thereof between said retracted and said projection position, support means mounted on said frame at a longitudinally stationary position relative to said guide means for movably supporting said lance tube at a position adjacent to the port, drive means for moving said lance tube between said positions, said support means including means movable in a direction transverse to the path of travel of said lance tube drivingly coupled to said drive means for effecting a controlled lifting and lowering of said lance tube supported thereby in coordinated relationship relative to the projecting length of said lance tube beyond said support means into the interior of the heat exchanger apparatus and in an amount to compensate for the downward gravitational deflection of said nozzle end thereof.

3. A long retracting type soot blower comprising a frame mounted exteriorly of a heat exchanger apparatus, guide means on said frame and extending longitudinally thereof, a carriage movably mounted on said guide means, a lance tube formed with at least one nozzle in the forward end thereof for discharging a blowing medium against the heat exchanger surfaces to be cleaned, said lance tube adapted to be positioned exteriorly of and in alignment with a port in a wall of a heat exchanger apparatus and movable to and from a retracted position wherein the nozzle end of said lance tube is disposed adjacent to the port and a projected position within the interior of the heat exchanger apparatus, the rearward end portion of said lance tube supported by said carriage in substantially constant spaced relationship from said guide means during the travel thereof between said retracted and said projection position, support means mounted on said frame at a longitudinally stationary position relative to said guide means for movably supporting said lance tube at a position adjacent to the port, first drive means for moving said lance tube between said positions, said support means movable in a direction transverse to the path of travel of said lance tube including second drive means for elfecting'a controlled lifting and lowering of said lance tube supported thereby in coordinated relationship thereto to the projecting length of said lance tube beyond said support means into the interior of the heat exchanger apparatus and in an amount to compensate for the downward gravitational deflection of said nozzle end thereof.

4. A long retracting type soot blower comprisinga frame mounted exteriorly of a heat exchanger apparatus, guide means on said frame and extending longitudinally thereof, a carriage movably mounted on said guide means,

a lance tube formed with at least one nozzle in the forward end thereof for discharging a blowing medium against the heat exchanger surfaces to be cleaned, said lance tube adapted to be positioned exteriorly of and in alignment with a port in a wall of a heat exchanger apparatus and movable to and from a retracted position wherein the nozzle end of said lance tube is disposed adjacent to the port and a projected position within the interior of the heat exchanger apparatus, the rearward end portion of said lance tube supported by said carriage in substantially constant spaced relationship from said guide means during the travel thereof between said retracted and said projection position, support means mounted on said frame at a longitudinally stationary position relative to said guide means for movably supporting said lance tube at a position adjacent to the port, drive means for moving said lance tube between said positions, said support means movable in a direction transverse to the path of travel of said lance tube including means drivingly coupled to said lance tube and operative in response to the projecting and retracting movement thereof for effecting a controlled lifting and lowering of said lance tube supported thereby in coordinated relationship relative to the projecting length of said lance tube beyond said support means into the interior of the heat exchanger apparatus and in an amount to compensate for the downward gravitational deflection of said nozzle end thereof.

5. A long retracting type soot blower comprising a frame mounted exteriorly of a heat exchanger apparatus, guide means on said frame and extending longitudinally thereof, a carriage movably mounted on said guide means, a lance tube formed with at least one nozzle in the forward end thereof for discharging a blowing medium against the heat exchanger surfaces to be cleaned, said lance tube adapted to be positioned exteriorly of and in alignment with a port in a wall of a heat exchanger apparatus and movable to and from a retracted position wherein the nozzle end of said lance tube is disposed adjacent to the port and a projected position Within the interior of the heat exchanger apparatus, the rearward end portion of said lance tube supported by said carriage in substantially constant spaced relationship from said guide means during the travel thereof between said retracted and said projection position, support means mounted on said frame at a longitudinally stationary position relative to said guide means for movably supporting said lance tube at a position adjacent to the port, drive means for moving said lance tube between said positions, said support means including a support member disposed in supporting contact with said lance tube and movable in a direction transverse to the path of travel of said lance tube for effecting a lifting and lowering thereof, cam means associated with said support member for effecting movement thereof, and means drivingly coupled to said drive means and said cam means for effecting a controlled lifting and lowering of said lance tube by said support member in coordinated relationship relative to the projecting length of said lance tube beyond said support means into the interior of the heat exchanger and in an amount to maintain said nozzle end in a substantially linear path of travel between said positions.

6. A long retracting type soot blower comprising a frame mounted exteriorly of a heat exchanger apparatus, guide means on said frame and extending longitudinally thereof, a carriage movably mounted on said guide means, a lance tube formed with at least one nozzle in the forward end thereof for discharging a blowing medium against the heat exchanger surfaces to be cleaned, said lance tube adapted to be positioned exteriorly of and in alignment with a port in a wall of a heat exchanger apparatus and movable to and from a retracted position wherein the nozzle end of said lance tube is disposed adjacent to the port and a projected position within the interior of the heat exchanger apparatus, the rearward end portion of said lance tube supported by said carriage in substantially constant spaced relationship from said guide means during the travel thereof between said retracted and said projection position, support means mounted on said frame at a longitudinally stationary position relative to said guide means for movably supporting said lance tube at a position adjacent to the port, first drive means for moving said lance tube between said positions, said support means including a support member disposed in supporting contact with said lance tube and movable in a direction transverse to the path of travel of said lance tube for effecting a lifting and a lowering thereof, cam means associated with said support member for effecting movement thereof, second drive means drivingly coupled to said cam means and operable to effect a controlled lifting and lowering of said lance tube by said support member in coordinated relationship relative to the projecting length of said lance tube beyond said support means into the interior of the heat exchanger and in an amount to maintain said nozzle end in a substantially linear path of travel between said positions.

7. A long retracting type soot blower comprising a frame mounted exteriorly of a heat exchanger apparatus, guide means on said frame and extending longitudinally thereof, a carriage movably mounted on said guide means, a lance tube formed with at least one nozzle in the forward end thereof for discharging a blowing medium against the heat exchanger surfaces to be cleaned, said lance tube adapted to be positioned exteriorly of and in alignment with a port in a wall of a heat exchanger apparatus and movable to and from a retracted position wherein the nozzle end of said lance tube is disposed adjacent to the port and a projected position within the interior of the heat exchanger apparatus, the rearward end portion of said lance tube supported by said carriage in substantially constant spaced relationship from said guide means during the travel thereof between said retracted and said projection position, support means mounted on said frame at a longitudinally stationary position relative to said guide means for movably supporting said lance tube at a position adjacent to the port, first reversible motor means for moving said lance tube between said projected and said retracted positions, said support means including a support member disposed in supporting contact with said lance tube and movable in a direction transverse to the path of travel to said lance tube for effecting a lifting and a lowering thereof, cam means associated with said support member for effecting controlled movement thereof, second reversible motor means drivingly coupled to said cam means, said second motor means energizable in response to energization of said first motor means and reversible in response to reversal of said first motor means, actuator means associated with said cam means, switch means actuable in response to said actuator means for deenergizing said second motor means when said cam means have returned to a preselected position at the completion of the retracting movement of said lance tube, said second motor means operable for effecting a controlled lifting and lowering of said lance tube by said support member in coordinated relationship relative to the projecting length of said lance tube beyond said support means into the interior of the heat exchanger and in an amount to maintain said nozzle end in a substantially linear path of travel between said positions.

8. A long retracting type soot blower comprising a frame mounted exteriorly of a heat exchanger apparatus, guide means on said frame and extending longitudinally thereof, a carriage movably mounted on said guide means, a lance tube formed with at least one nozzle in the forward end thereof for discharging a blowing medium against the heat exchanger surfaces to be cleaned, said lance tube adapted to be positioned exteriorly of and in alignment with a port in a Wall of a heat exchanger apparatus and movable to and from a retracted position wherein the nozzle end of said lance tube is disposed adjacent to the port and a projected position within the 13 interior of the heat exchanger apparatus, the rearward end portion of said lance tube supported by said carriage in substantially constant spaced relationship from said guide means during the travel thereof between said retracted and said projection position, support means mounted on said frame at a longitudinally stationary position relative to said guide means for movably supporting said lance tube at a position adjacent to the port, drive means for moving said lance tube between said positions, said support means including a support member disposed in supporting contact with said lance tube and movable in a direction transverse to the path of travel of said lance tube for effecting a lifting and a lower iiig thereof, cam means associated with said support member for effecting movement thereof, a sprocket drivingly coupled to said cam means, a continuous chain trained around said sprocket having a section thereof operatively connected to said lance tube for movement thereby and rotation of said sprocket in response to the translatory movement of said lance tube providing movement of said support member effecting a controlled lifting and lowering of said lance tube in coordinated relationship relative to the projecting length of said lance tube beyond said support means into the interior of said heat exchanger and in an amount to maintain said nozzle in a substantial linear path of travel between said positions.

References Cited by the Examiner UNITED STATES PATENTS 3,160,907 12/64 Tollow 153l7 ROBERT W. MICHELL, Primary Examiner. 

1. A LONG RETRACTING TYPE SOOT BLOWER COMPRISING A FRAME MOUNTED EXTERIORLY OF A HEAT EXCHANGER APPARATUS, GUIDE MEANS ON SAID FRAME AND EXTENDING LONGITUDINALLY THEREOF, A CARRIAGE MOVABLY MOUNTED ON SAID GUIDE MEANS, A LANCE TUBE FORMED WITH AT LEAST ONE NOZZLE IN THE FORWARD END THEREOF FOR DISCHARGING A BLOWING MEDIUM AGAINST THE HEAT EXCHANGER SURFACES TO BE CLEANED, SAID LANCE TUBE ADAPTED TO BE POSITIONED EXTERIORLY OF AND IN ALIGNMENT WITH A PORT IN A WALL OF A HEAT EXCHANGER APPARATUS AND MOVABLE TO AND FROM A RRETRACTED POSITION WHEREIN THE NOZZLE END OF SAID LANCE TUBE IS DISPOSED ADJACENT TO THE PORT AND A PROJECTED POSITION WITHIN THE INTERIOR OF THE HEAT EXCHANGER APPARATUS, THE REARWARD END PORTION OF SAID LANCE TUBE SUPPORTED BY SAID CARRIAGE IN SUBSTANTIALLY CONSTANT SPACED RELATIONSHIP FROM SAID GUIDE MEANS DURING THE TRAVEL THEREOF BETWEEN SAID RETRACTED AND SAID PROJECTION POSITION, SUPPORT MEANS MOUNTED ON SAID FRAME AT A LONGITUDINALLY STATIONARY POSITION RELATIVE TO SAID GUIDE MEANS FOR MOVABLY SUPPORTING SAID LANCE TUBE AT A POSITION ADJACENT TO THE PORT, SAID SUPPORT MEANS INCLUDING MEANS MOVABLE IN A DIRECTION TRANSVERSE TO THE PATH OF TRAVEL OF SAID LANCE TUBE FOR EFFECTING A CONTROLLED LIFTING AND LOWERING OF SAID LANCE TUBE SUPPORTED THEREBY IN COORDINATED RELATIONSHIP RELATIVE TO THE PROJECTING LENGTH OF SAID LANCE TUBE BEYOND SAID SUPPORT MEANS INTO THE INTERIOR OF THE HEAT EXCHANGER APPARATUS AND IN AN AMOUNT TO COMPENSATE FOR THE DOWNWARD GRAVITATIONAL DEFLECTION OF SAID NOZZLE END THEREOF. 